1. Field of the Invention
The present invention relates to a method of manufacturing a fuel tank for automobiles, and more particularly to a method of manufacturing a fuel tank of synthetic resin formed by blow molding.
2. Description of the Prior Art
A method of manufacturing a fuel tank of synthetic resin by blow molding in the prior art is disclosed, for example, in Japanese Patent Laid-open Publication No. Sho 61-89824.
In the method disclosed in this reference, a baffle plate as a wave eliminating member is set as an insert to a mold for blow molding, and an outside wall of the tank is formed by blow molding and the baffle plate is fixed to the inner circumferential surface of the outside wall. The fuel tank of synthetic resin is thereby manufactured.
However, the fuel tank is usually provided at the inside with parts to construct definite functions, such as a fuel level gauge, a fuel cutoff valve, a fuel pump or the like. Consequently, when these parts are installed to the fuel tank, the outside wall formed by blow molding is provided with a hole for mounting, and parts are mounted through the hole. In this case, in order to secure the air tightness at the periphery of the hole after the mounting, a prescribed rubber part for a seal becomes necessary.
Consequently, in the manufacturing method of the prior art disclosed in this reference, when a fuel tank as a final product having prescribed parts is manufactured, after an outside wall is formed by blow molding, not only parts must be assembled but also boring machining or assembling of a rubber part for a seal must be performed, thereby increasing the manufacturing process number and the cost.